1. Field of the Invention
The present invention relates to a master roll for a stencil and a master roll holding apparatus for holding the master roll.
2. Description of the Prior Art
A printing apparatus such as a stencil printer provides a stencil portion. The stencil portion holds a master roll, which is wound around a core such as paper core, with a master roll holding apparatus. The stencil portion makes a master by heating the stencil so as to generate stencil pattern. The stencil printer prints the image according to the stencil pattern while the stencil generated the stencil pattern is wound around a plate cylinder.
FIG. 19 is an elevational view in section of a conventional master roll 200 and a pair of flange plate 201 comprising a part of a master roll holding apparatus. A long-formed stencil 203 wound around a cylindrical paper core 202 forms the master roll 200. One sides of the flange plates 201 provides convex connectors 204, which is inserted into the inner periphery of the paper core 202. Another sides of the flange plates 201 provide support pins 205. The support pins 205 should be inserted into the support grooves (not shown) provided on the support tables (not shown) after the convex connectors 204 are inserted into the inner periphery of the paper core 202, when an operator desires the master roll to set on the master roll holding apparatus.
A master roll holding apparatus, which inserts a convex connector provided on the fixed flange into the core of the master roll so as to hold the master roll, is also known.
The master roll has a variety with respect to the size or the like. Thus, there may be proper master roll and improper master roll for each stencil printer. Then, it is hopeful to be able to easily confirm whether certain master roll is proper or improper, when the operator desires the master roll to use on certain stencil printer.
One simple solution for confirmation of proper or improper master roll is obtained by definition of the inner diameter “d” of the paper core in accordance with variety of the master roll.
Japanese laid open publication No. Hei 5-290227 discloses other solution of the same. This document shows identity marks, on the inner or outer periphery of the paper core, which can be detected by a sensor.
Japanese patent publication No. 2863319 discloses other solution of the same. This document shows printed identity marks, on the end of the master roll, which can be detected by a sensor.
Further, Japanese patent publication for opposition No. Hei 4-20605 discloses techniques for preventing reverse setting of the master roll on the master roll holding apparatus. This document shows the core whose both ends are projected from the ends of the stencil such as the projected amounts thereof are different each other.
Herein after, drawbacks of the above master roll will be described.
It is simple and easy understanding that the inner diameter “d” of the paper core is defined in accordance with variety of the master roll for confirmation of proper or improper master roll. However, this method requires manufacturing several variety of the core while the core is manufactured. This is so complicated. Also many variety of the master roll cannot be obtained because the variation of the inner diameter “d” is not so many.
The method described in Japanese laid open publication No. Hei 5-290227 also requires manufacturing several variety of the paper core having the identity marks while the paper core is manufactured. It is supposed to print the identity marks after manufacturing the paper core by a printer, but the printer should be expensive.
The method described in Japanese patent publication No. 2863319 has a drawback that the marks may not be detected surely if the master roll is reused after detaching and attaching the used master roll.
A master roll holding apparatus described in Japanese patent publication for opposition No. Hei 4-20605 can prevent the reverse setting of the master roll, but cannot allow the master roll to confirm whether the master roll is proper or improper for the stencil printer.